Dr. Anthony Chaffee provides a comprehensive breakdown of human digestive anatomy to demonstrate why humans are evolved carnivores, not herbivores. He explains how humans have extremely low stomach pH (around 1.4) similar to scavengers, a long small intestine optimized for absorbing proteins and fats, and a vestigial appendix that proves we lost our fiber-digesting capabilities millions of years ago. Unlike true herbivorous primates with large cecums for bacterial fiber breakdown, humans cannot digest fiber at all and instead evolved four organs working together specifically to absorb fat.

The discussion reveals how the common belief that fat causes gallstones is backwards - gallstones actually form when people avoid fat, allowing bile to concentrate and crystallize in the gallbladder. Dr. Anthony Chaffee explains that eating adequate fat daily prevents stone formation by ensuring regular bile excretion, and cites how humans can absorb 98% of meat even as infants, while fiber requires medical elimination during digestive healing.

Key Takeaways

  • Humans have stomach acid pH of 1.4, similar to scavenging animals, proving our evolutionary adaptation to breaking down meat rather than plant matter
  • Gallstones form from avoiding fat, not eating it - consuming adequate daily fat prevents stone formation by ensuring bile doesn't concentrate in the gallbladder
  • Human infants can absorb 98% of meat on first exposure, while adults absorb nearly 100% of properly prepared muscle meat with minimal digestive residue
  • The human appendix is a vestigial cecum, proving we lost our fiber-digesting capabilities millions of years ago unlike other herbivorous primates
  • Human Digestive Anatomy vs Other Primates - Stomach Acid and Carnivore Adaptations
  • Why Humans Can't Digest Fiber - Lost Cecum and Appendix Evidence
  • Gallstones Myth - How Low-Fat Diets Actually Cause Gallstones
  • Carnivore Digestion Superiority - 98% Meat Absorption vs Fiber Problems

This is an auto-generated transcript from YouTube and may contain errors or inaccuracies.

hi this is dr chafee uh today i just wanted 
to talk a bit about digestion everyone talks   about the differences between different 
animals and their digestion to say well   humans are herbivores because we have digestion 
like a cow or an herbivore this than the other   or we're a carnivore because of you know the same 
arguments but nobody knows exactly what means   anything and what the main principles are and what 
the main points are so when you're having these   discussions here are some of the main points so we 
are primates okay so we have a primate digestion   okay so we're going to have adaptations in one 
direction or another but they're fundamentally   going to be primate so they're going to be 
very similar to a gorilla or a chimpanzee or a   tarcy or something like that but we're gonna 
be having have some subtle differences so   people think that because we have a similar 
digestion to other primates that must mean   that we're herbivores like those herbivorous 
primates but not all primates are herbivorous and   you know so that really doesn't uh make a strong 
argument we have uh some things that are very   uh typical for carnivores we have very low stomach 
ph okay so it actually goes down to around like   1.4 which is extremely extremely acidic and this 
is this is generally what we see with people um or   sorry animals that are uh even you know scavengers 
like vultures okay it's thought that early on in   our meat eating heritage millions of years ago 
that we were eating uh carrion and we weren't able   to take down and kill animals ourselves because we 
didn't have big teeth and cloths we were actually   eating the remains of what other animals left 
and we were figuring out how to do that we're   getting smarter using tools and you know using 
stones to crack open the skulls to get the brains   and that was giving us nutrition we started 
figuring out other ways of using tools as well   and that's why our brains developed instead of our 
teeth and our claws okay we also have very long   small intestine okay and this is where all the 
proteins and fats and and other nutrients and   vitamins all get absorbed okay so we get a lot 
of our the majority of our nutrition comes from   there the vast majority of what we eat gets 
absorbed in the small intestine so we need a   longer small intestine just like other carnivores 
our large intestine is actually very small so   these these things are um a bit you know misnamed 
really but you know small in the sense of length   not as diameter which is what we call a large 
intestine large because it's a bigger diameter   so this is something that we don't really 
see in in herbivores herbivores have a longer   large intestine and in fact primates 
when you look at them specifically   they are hind gut digesters if they're if 
they're herbivores okay so they have a very long   large intestine and a very long cecum which 
helps them break down plant material and fiber   and actually get the majority of the nutrition 
comes from that breakdown of that fiber okay so   no vertebrate animal can break down fiber okay so 
certain animals like a cow or like a gorilla have   been able to basically farm bacteria that eat this 
that eat this fiber and as a byproduct basically   their waste are short chain fatty acids okay which 
is or just saturated fats are 100 saturated and so   that's what the animal actually absorbs okay so 
what they eat and what they put in their mouths   is not the same thing as what they absorb okay 
what they absorb are these short chain fatty acids   and and proteins that are a byproduct of those 
bacteria eating fiber and breaking it down okay   we can't do that that's how you know we're 
not like other other primates and we're not   herbivorous because we lost that ability millions 
of years ago we have an appendix an appendix   is a vestigial cecum okay in a gorilla or or a 
chimpanzee it was very long like four foot long   ours is about that big okay vesial meaning that 
it it's an organ that used to do something now it   does nothing and it has it for millions of years 
because we haven't used it in millions of years   okay and so the cecum that blinds out pouching 
used to be where our ancestors would you know   get their nutrition from fiber and that's 
where gorilla gorillas and so forth that's   where that packs in and they break down that 
fiber and get the short chain fatty acids okay   so we can't do that we've lost that ability 
because we were eating meat for millions of   years and that's just further evidence that 
we're carnivores and that our ancestors and we   are who we are because our ancestors became 
carnivores millions of years ago okay so   you know all herbivores that eat fibrous plants 
are able to break down fiber to to a certain   extent okay and we can't do that so that that is 
a cardinal feature of us not being herbivores okay   so the other issue is bile this is something 
that comes up a lot people talk about   how you know if you eat meat or you eat fat you're 
going to get gall stones this is a supposition   this is something that has been bandied around 
because it sort of fit the you know the observable   evidence but it is completely and utterly 
wrong okay so in medicine we talk about the   four f's for gallstones these are risk factors 
it's not a guarantee but it's a risk factor   female fertile 40s fat okay and or and 
fair is another one you know people of   of uh light complexion seem to 
get this stuff more often but this is not one-to-one they say well this 
person's fat therefore because they ate fat   they've got they've gotten fat and they've 
gotten gallstones but people don't get fat   from eating fat they get fat from 
eating carbohydrates and sugar   okay so it wasn't the fat in the first place that 
got them fat but what you do see commonly in this   thread of people i mean think about it you have 
you know a lady who's in her 40s just had a   couple kids has a little bit extra baby weight 
and wants to lose that weight okay wants to get   her body back and so she goes on a diet well what 
have everybody been told for the last 40 years   is if you want to lose fat you stop eating 
fat and so these people want to lose this   fat they want to lose the baby weight so they stop 
eating fat okay and that is actually the problem   your body makes bile so that you can absorb 
fat okay it's very difficult for your body to   absorb fat without bile there's there's some 
medium chain fatty acids which can just be   uh you know absorbed you know on their 
own but nearly all other fats need bile   it's very difficult for your body to absorb bile 
to absorb fat without bile okay your body makes a   certain amount of this okay about 800 milliliters 
to a liter a day and now you know maybe that can   change depending on on what you're eating and 
what your body requires and so forth but there   is a limit and then there is a finite amount 
of bile that it makes okay it's slow processed   this is made and then stored in your gallbladder 
okay then when you eat that it squishes it out   and bile goes down absorbs that fat so you know 
i mean as a side note it's kind of ridiculous   for people to argue that fat is bad for us if we 
have four organs working in concert just to absorb   fat liver makes bile your gallbladder stores it 
your pancreas secretes enzymes to break it down   and your small intestine absorbs it into your body 
okay you know that that's a lot of energy uh for   your for your body and evolutionarily biologically 
you know it doesn't make any sense for you to   build that system and evolve that system if that 
wasn't really really really important okay which   it is all right so what happens to these people 
that get gallstones problem is they don't eat fat   right if you were to eat as much fat as you had 
bile for which i take to mean as much as your   body wants okay then you're going to excrete all 
the all the bile that's in your gallbladder right   every day so even if you were someone who had 
some weird condition that meant that you would   get gall stones in just one day you could never 
get gallstones if you were eating enough fat   you couldn't possibly because the bile wouldn't 
be there in your gallbladder to form stones in   the first place okay it physically cannot 
take place if you're eating enough fat   okay so you get these people that go on a diet 
stop eating fat and then all of a sudden six   weeks later eight weeks later when they go off 
the diet all of a sudden they go oh that hurts   because now their body's trying to squish out 
the bile but there are stones in it and they get   stuck and that hurts and they go to the doctor and 
they say it's because you're eating too much fat   well no actually it's because they weren't 
eating fat okay and they stopped eating fat   okay because your bile goes into your gallbladder 
but it doesn't just run you know when it runs out   of room it doesn't just sit there okay it you 
know it concentrates okay not everyone knows   this but even in the textbook it describes 
bile as being able to get up to 20 times   more concentrated than when it originally comes 
out of the liver so there may be people that   get more concentrated than other people and maybe 
those people are more predisposed to uh gallstones   maybe that'd be interesting to look into because 
certainly not everybody gets gallstones even   if they just stop eating fat entirely okay so 
there's probably something else going on as well   but you know the take home is if you eat enough 
fat it doesn't matter you cannot form stones okay   so bile goes into your gallbladder it gets more 
and more concentrated more and more concentrated   what happens to any hyper concentrated solution 
at rest it forms precipitates you perform it forms   stones okay that's what bile sludge is that's what 
gallstones are okay and you see this in bariatric   medicine as well because when people remove parts 
of the stomach and the lower intes and the the the   first part of the duodenum and the small intestine 
and so forth or put in a sleeve and and what have   you you know many different different surgeries 
in that in that realm but a lot of these people   much more than the rest of the population even the 
overweight population will develop gallstones a   lot of them do okay and i've heard this described 
as well you know something changes metabolically   when you when you when you lose weight really 
fast that somehow that makes you form these stones   okay maybe it does but you still want won't 
form stones if you get enough fat and what is   the commonality between these people these people 
are really serious about losing weight they really   don't want to be overweight anymore they're going 
through very dangerous life-threatening surgery   and can threaten your life and it can threaten 
your quality of life and can threaten your your   happiness going forward i've seen um several 
people that i know personally have had you know   very bad results from this and have serious health 
issues afterwards so this can seriously affect you   but they're very serious about this and so what 
do they do they're going to stop eating that all   together and i've heard people say this when they 
get the gallstones they say you know that can't be   because i have not eaten any fat in months and 
you know to me that that's why they got gallstones   okay so it's not that they lost a lot of fat 
or lost a lot of weight quickly it's how they   lost a lot of weight quickly it's by just 
completely eliminating fat altogether okay so   these are all things that point in the direction 
of we're carnivores because we're meant to be   eating fat right the reason we've been told not 
to eat animals and not to eat plants is because   they have fat but that's actually very obvious 
that we should be doing that because we have   four organs working together in order to make uh 
make it possible to absorb fat okay and we have   very low ph uh stomach acid and this is a side 
note so a lot of people will get better digestion   if you don't drink water sort of two hours before 
after a meal because you keep that that uh stomach   acid more concentrate so you'll break food 
down better okay so we've got very concentrated   ph okay we've got a long small intestine we've 
got a short large intestine we have a vestigial   appendix not a cecum we can't break down fiber 
we've got uh four organs working to absorb fat   okay um you can argue day and night about the 
anatomy of these things i'm sure someone has a   rebuttal to why i'm completely wrong even though 
they're wrong but it comes down to functionality   we don't break down fiber at all period okay 
so it's really hard for us to process any plant   material at all that contains fiber okay we break 
down liquefy and absorb meat very easily even even   infants and studies in the 1950s were showing that 
when being fed meat for the first time or anything   for the first time they were being given meat 
they would absorb 98 of what they were given okay   dr salisbury of the salisbury steak he made the 
salisbury steak specifically because you ground   the meat in a very specific way to get the gristle 
out and you just had the muscle meat and you just   had the fat you didn't have the gristle and 
the connective tissue and they were finally   you absorbed basically 100 of that so people that 
had very serious digestive issues like you know   crohn's and ulcerative colitis and and so forth uh 
and it was 100 years before we had any treatments   for this you know these people had horrible 
digestions they had extreme pain they were at   bloody diarrhea constantly every day and so these 
people really needed to rest uh their bowels and   so forth and so that's why salisbury came up with 
the salisbury steak so this had like zero residue   and they could just rest and this is what we do 
in surgery as well for the general surgeons when   you have diaviculitis appendicitis says you're not 
treating surgically you're treating conservatively   you will rest the bowel by giving them a low a 
low fiber diet you know if fiber is so good for   your digestion it's so good for your intestine why 
why do we need to get rid of it when we're resting   your bowel you know that that doesn't that should 
should make you ask questions now maybe there's   an instance that that that that's holds true but 
it should make you wonder if this is so good for   your body wouldn't you wouldn't you want it when 
your body's trying to heal that exact organ no   in fact there are studies that show that um the 
only you know correlation between you know eating   all these sorts of things and diverticulosis 
which is the outpouching the failure of the   the distal colon that can then get infected and 
so forth and get diverticulitis and cause you big   problems the only things that were associated with 
increased rates of divertic diverticulosis were   increased number of bowel motions a day increased 
fiber intake okay you're overworking the organ   you're making this work work work work work and it 
finally just fails just like heart failure you're   pumping against a high gradient of high pressure 
all the time and after several years you know   just wears out you get you get failure well this 
is colon failure okay and that's because you're   overusing it you're overworking it okay whereas if 
you eat a low residue diet like a carnivore diet   or you're not eliminating waste all that often 
because there's there's no waste to eliminate   right then you know that doesn't that doesn't go 
into failure you know and that just just another   thing you know say that you know you can't you 
know you can't really digest meat that just stays   in your intestine in rots for years if anybody 
thought about that for more than one second   they realize that's insane because your 
digestion is a tube it's a one-way tube   it just goes out and so if you 
weren't digesting this you'd just be   crapping out lumps of meat every day but you 
don't you crap out lumps of wood which is fiber   that's what we're we're excreting and we're being 
told oh no no but that's that's good for you we   absorb this so easily and yet we don't absorb 
it at all we don't break it down at all okay we   cannot break down the fundamental structure of 
plants which is fiber we break down and absorb   basically 100 percent of animal tissue so i hope 
that was informative i hope you guys like that and   yeah let me know in the comments what other sorts 
of videos you'd like to hear about take care
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